Wayside equipment in a transportation network may be used to help determine location of a vehicle as the vehicle travels in the network. For example, a wayside device may transmit a beacon or signal used by a vehicle to determine an approximate position of the vehicle. Some transportation systems, including systems operating under the European Train Control System (ETCS) standard, utilize Balise Transmission Modules (BTMs). The current BTM/ETCS standard implements data communication between a train and wayside infrastructure (e.g., a balise mounted along a route of the network) using two independent wireless links. A telepowering high power transmission from onboard equipment is sent via a first wireless link (down-link), and information is transmitted from the wayside equipment to the vehicle via a second wireless link (up-link).
Current systems base balise detection on received signal strength indication (RSSI) measurements of up-link signal strength. The up-link transmission is based on inductive transponders (e.g., balises), that are available from different manufacturers. The equipment may perform up-link transmission and telepowering in different ways based on different manufacturing sources and/or specifications, creating discontinuity from the transmission point of view, resulting in inaccuracy of position determinations. Further, inductive transponders used with current RSSI detection methods do not provide desired accuracy in balise position measurement, and may be prone to false detection due to cross-talk with adjacent tracks. Further still, as balises or other wayside equipment may be exposed to challenging environments, the equipment may suffer damage, and be unable to send a recognizable signal.
Alternative approaches may employ image processing for object detection. However, these approaches may suffer the drawbacks of requiring considerable post-processing computational burden as well as additional complexity and costs of onboard equipment.